Process of refining lubricating oils



Nw. S, 1927.. 11,649,095

. O. c. BRESTER Pnocss oF REFINING LUBRICATING-oms Filed Oct. 18. 1921 2Sheets-Sheet l QQ SQ ...IMU HHHIIIH Hfdlllllllhu INVENTQR da M MMM/mfWITNESS:

Nov, 15, 1927. 1,949,095

o. c. BREws-a-ER PROCESS OF REFINING LUBRICATING OILS Filed oct. 18,1921 2 Smets-sheet 2 afrzwzef I v INVENTOR ATTORNEY WITNESS:

Patented or. l5, l2?.

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@SWJMLB C. BREWSTER, OF CAS-PER, WYOMING, ASSIGNOE. T THE SHARIPLES SPEf CIALTY COMPANY, A CORPORATION OF DELAWARE.

rnocnss or Rnrrmne Lunnrcarrno otrs.

Application filed October 1.8, 1921. `Serial No. 508,530.

The present invention relates 4to the-.treatmentyof lubricating oils forthe removal of waxy materials, namely, `materials whlch are liable tosolidify when the temperature of 5 the oil is reduced. Uils containingwaxes are less desirable for certain classes of lubrication. The removalof the wax improves the cold test of the oil.

1t has heretofore been proposed to dilute l0 lubricating oil of thecharacter referred to with a solvent thereof such as naptha or gasoline,to refrigerate the mixture, and to inject the refrigerated mixture,together with a refrigerated carrier liquid of about the sametemperature, intoy a centrifugal bowl separator, the liquid oil flowingout from the outlet nearest the center and the carrier liquid and waxflowing out through the outlet nearest the periphery.

lin accordance with the present invention,

ll preferably dilute the lubricating oll'with a light hydrocarbon liquidsuch as naptha or benzine, the amount of dilution depending upon theviscosity of the o1l and the amount of waxy material which it contains.

ll then pass the said diluted oil, in a refrigerated condition, througha centrifugal bowl separator, in which is provided a substantiallystationaryti. e. a non-progressing) carrier liquid, which liquid isrefrigerated by the refrigerated mixture of solution (oil and solvent)and solid waxy material held in suspension, which is introduced. rll`hecarrier liquid originally placed in the bowl remains, as a film or layercovering theV side of the bowl, and it is not necessary to continue tointroduce carrier liquid with the mixture .as was done in the priorprocess above referred to. ll withdraw the wax from the oilcontinuously, from the centrifu al bowl separator, and preferably at theen oppositeto where the refrigerated mixture is introduced. lt is to beunderstood that the introduction and withdrawal are substantiallycontinuous.

During the operation of the centrlfugal process the wax is separated inthe centrifugal bowl from the oil, and the wax passes into acompartment, through which it moves to its outlet from' the bowl, assubstantially solid wax. 'llhe wax in this compartment is melted byintroducing into said compartment a hot liquid, which liquid ispreferably of the same character and same density as the carrier liquidforming the stationary or non-progressing film or layer on the interiorof the bowl.

rlhe process will be described more in detail in connect-ion with theannexed drawings in which Fig. 1 represents in a diagramma-tic Way, anelevation of the entire apparatus, three centrifugal machines beingshown therein, but it is obvious that any desired number can beemployed. vFigure 2 represents a horizontal section with parts brokenaway of a preferred form of the centrifugal separator, which lpreferably employ in carrying out the process, taken approximately online 2-2 of Figure 4f. Fig. 3 is a detailed section with parts brokenaway of the upper part of the preferred centrifugal separator shown inFig. 2, and Fig. d, is a vertical section with parts broken away of apreferred construction of the upper part of the same centrifugal liquidseparator.

lin carrying out the process, the refrigera-ted oil or preferably therefrigerated mixture of oil and solvent with precipitated .y

waxy material enters through pipe 10, pipe 11 and pipe 12 into a tank 13in which a constant head of liquid is maintained, for example by asuitable float in the tank connected with' a valve in pipe 12, 'llheliquid flows downwardly continuously through pipe 14 into the header 15from which it is supplied continuously in regulated quantities to thecentrifugal machines, by the valve pipes 16, 17 and 18. rllhe bowlsofthe centrifugals which are usually vertical) Valready carry the filmof carrier liquid, which may be any liquid which is not miscible withthe oil or solution or oil under treatment, "a solution of calciumchloride, common salt or the like, or in some cases clear water beingsuitable for .the purpose. There is then produced in the centrifugalbowl three strata, the outermost or heaviest beingr the carrier liquid,the next being the precipitated wax and the innermost being the oil andsolvent freed from wax by the centrifugal action. rlhe liquid oil andsolvent overfiows (passes linside of) the ring dam 20 and passesupwardly through the channels 21 into the upper cover 22, from which itfalls down on to the plate 23 and is drawn off through spout 24. The waxpasses under (outside of) the edge 25 of the dam, and into the space 26.'llhe wax is melted by hot carrier liquid introduced vided with a narrowslit or small holes v29 at its lower end. This liquid 1s projected intothe space 26 by means of ns or blades 30 th left hand one being bentbackward and the right hand one being bent forward. The middle one ofthese three fins shows the preerred amount of'bending. These iins,rap1d-1y rotating, engage the liquid projected from 29 and impart to suchliquid the same rotary motion which the bowl has, and project theliquidl downwardly into the compartment 26. This liquid is hot andaccordingly melts the wax in the compartment 26, the molten wax and hotcarrier liquid owing out over the ring dam 32, intov the spacev 33 on tothe lower cover 34 and out through the spout 35 which spout may be, Vasshown in Fig. 4, on the same side of the machineas the spout 24, orthese two spouts may be on opposite sides, as shown in Fig. 1.

During the centrifugal separating operation the oil weir or dam A20 andthe wax Weir or dam 32 bear such. relation to the axis of the bowl andto each other that separation to a desired degree will occur and theliquid balance will be maintained in the bowl. Thus, centrifugal forceof the strata of 'oil and wax below the ring dam 20-25 will be in liquidbalance with thecentrifugal force of a supplemental body of li uidconsisting of the carrier liquid (and w iatever Wax is containedtherein) inthe compartment 26 which lies between dam 20-25 and dam 32,.but the Weir 32 is so adjusted that the stratum of wax has the properthickness in a radial direction to insure proper separation of the waxfrom oil and (the dischar e of substantially oil-free wax. The centriugal bowl is preferably operated at high speed, for example, 15,000

revolutions per minute.

VThe amount of hot liquid injected through 27 is preferably such as tomaintain the wax in. a freely molten condition in the spout 35,

pipes 36, header 37 and pipe 38. The mixture of wax and carrier liquidflows into the separating tank40, which tank is provided with a suitableheating coil'41, a steam coil bein suitable for this purpose. In thetank 40 t e liquids stratify the -wax iiowing through/pipe 42 into atank 43, from which the wax can be drawn off and /further treated inanydesired way, for distilling olf the small amount of naptha present inthe wax and the productionv of petrolatum or other through pipe 44 intoa heatin suitable products. The hot carrier liquid which separates intank 40 is drawn off tank 45 in which the temperature of this iquid iskept up by a suitable coil 46. This liquid is pumped out through pipe,47, pump 48 and vpipe 49 into a liquid tank 50 which tank islikewiseprovided with a suitable steam coil three of which areillustratedv in Fig. 3,

or other heatingl coil 51. A pipe 52 from the upper part of the tank maycarry away any excess of carrier liquid taken into the tank 45. Theliquid from tank 50 ows through 55, 56 into the header 57, from whichbranch pipes 58 provided with suitable valves supply the liquid to pipes27.

The clear oil fiowing out from spouts 24 runs into spouts 60 into theheader 61 and may be drawn off at 62 either to a storage tank or to astill for separating the oil from the solvent, in case the latter wasused.

In the operation above described, in which carrier liquid is fed intothe wax discharge outlet of the bowl, there occurs a more completeseparation of wax and oil than in the operation in which carrier liquidis continuously fed to the bowl together with a mixture of wax, oil andsolvent. And, when the carrier liquid is fed hot into the wax dischargethe wax, which at the temperature of separation may be of a stiff andadhesive character, may' be disposed of and caused .to flow out of thespout 35 by adjustment of the amount of hot liquid introduced throughpipe 27 and the amount of mixture introduced through pipe 16.

The amount of dilution of the oil, in the first step of the processdepends largely on the gravity and viscosity of the oil and on Uil theextent to which it is desired to separate y specific gravity of the oil,and hence makes a greater difference in specific gravity between the oilsolution and the wax, thus facilitating the separation of the wax fromthe oil solution. In fact, in most stocks the wax is of slightly lowerspecific gravity than the oil and the addition of the light solventreverses this condition and makes the specific gravity of the oil muchless than that of the wax.

The carrier liquid forming the stationary film in the centrifugalispreferablyof the same composition as the hot carrier liquid introducedthrough pipe 27. While the layer of carrier liquid serving to furnish (africtionless `surface over which the layer ture attained by it in theseparator. In run-` ning solution chilled to 10 F. a 20-25 B. gravitysolution of calcium chloride has been. found suitable. In otherinstances clear water has been used when separating Voil and waxmixtures that have been chilled to a temperature between 1 F. and 35 ll.The carrierliquid introduced through pipe 27 is of sufliciently hightemperature to melt the waxes. A- range of from 17 0 Dl?. to 190 F. hasbeen found suitable depending on the melting point of the wax beingseparated. c

The temperature. conditions in the centrifug'al bowl will besubstantially uniform from the bottom of the bowl, where the liquid isintroduced, up to the dam 25, but

vwhen injecting relatively great quantities of hot liquid from 28, thetemperature might rise a few degrees, just below the dam 25.

However, the wax having reached this point,

and having been substantially separated from the oil, it will notredissolve therein to any appreciable extent.

l claim:

l. The method of treating oils which comprises the centrifugalseparation of mineral oil material comprising a waxy constituent capableof being easily melted in combination with the step of delivering a'hotcarrier v liquid to the centrifugal. rotor at the place of discharge ofthe said waxy constituent.

2. lin the process of cehtrifugally separatingv wax from petroleum oilby methods involving the passage of a refrigerated solu-` tion of suchoil into and through a centrifugal rotor in which separation iseffected, and in which is provided a layer of cold carrier liquid\lwithin which such oily material flows, the herein described stepofdirecting hot liquid into the Vwax outlet of the centrifugal rotor, suchhot liquid being in amountwsuliicientvto melt the lsaid wax,

andsuch hot liquid also h eing non-miscible with oil and no'n-lnisci-blewith molten wax.

3. ln the process of centrifugally sepalrating wax 'frompetroleum oil bymethods involving the passage of a refrigerated solution of such oilinto and through. a centrifugal rotor in which separation is effected, adin which is provided a layer of cold carrier liquid within which suchoily material flows,vthe herein described step of y directing a largenumberof streams ofwarm liquid into the wax outlet'of the centrifugalrotor, to melt the wax and flush it out of the centrifugal.

4. In a process of treating lubricating yoil containing waxyconstituents, which comprises passing a refrlgerated mixture of solventand such oil into a high speed cen-- trifugal liquid separator, whilethe ,rotating bowl of said centrifugal -contains carrier L liquidstationary relatively thereto which is v to centrifugal force in acentrifugal bowl v,and maintaining therein a body of carrier liquid,separately discharging the wax, and

feeding hot carrier liquid to the bowl at the natural place of dischargefor the wax.

6. lThe method which consists in subjectmga mixture of oil andprecipitated wax to centrifugal force in a centrifugal bowl andseparating and separately discharging the wax and oil, and feeding hotliquid into contact with the wax after its separation from the oil andprior to its discharge from the bowl. l

7. The method of separating 'wax from petroleum oil Vwhich com risesmaintaining. a main body of oil, containing wax precipitated bychilling, within the revolving rotor of a centrifugal machine andsubjecting it to centrifugal force to separate wax from within therotor, passing separated wax body, and feeding hot liquid into contactwith said supplemental body through the wax discharge and discharging.it therefromr with the wax.,

In testimonyl whereof I alix my signature.

OSWALD C. BREWSTER.

`the oil, maintaining a supplemental body 4from said main body into saidsupplemental

